- Floors. Floor furnaces shall not be installed in the floor of any doorway, stairway landing, aisle or passageway of any enclosure, public or private, or in an exitway from any such room or space.
- Walls and corners. The register of a floor furnace with a horizontal warm-air outlet shall not be placed closer than 6 inches (152 mm) to the nearest wall. A distance of at least 18 inches (457 mm) from two adjoining sides of the floor furnace register to walls shall be provided to eliminate the necessity of occupants walking over the warm-air discharge. The remaining sides shall be permitted to be placed not closer than 6 inches (152 mm) to a wall. Wall-register models shall not be placed closer than 6 inches (152 mm) to a corner.
- Draperies. The furnace shall be placed so that a door, drapery or similar object cannot be nearer than 12 inches (305 mm) to any portion of the register of the furnace.
- Floor construction. Floor furnaces shall not be installed in concrete floor construction built on grade.
- Thermostat. The controlling thermostat for a floor furnace shall be located within the same room or space as the floor furnace or shall be located in an adjacent room or space that is permanently open to the room or space containing the floor furnace.
The duct furnace shall be installed on the positive pressure side of the circulating air blower.
Means shall be employed on these lines to prevent water from entering and to prevent blockage by insects and foreign matter. An atmospheric vent line shall not be required to be provided on a valve train component equipped with a listed vent limiter.
|DRYER EXHAUST DUCT FITTING TYPE||EQUIVALENT LENGTH|
|4 inch radius mitered 45-degree elbow||2 feet, 6 inches|
|4 inch radius mitered 90-degree elbow||5 feet|
|6 inch radius smooth 45-degree elbow||1 foot|
|6 inch radius smooth 90-degree elbow||1 foot, 9 inches|
|8 inch radius smooth 45-degree elbow||1 foot|
|8 inch radius smooth 90-degree elbow||1 foot, 7 inches|
|10 inch radius smooth 45-degree elbow||9 inches|
|10 inch radius smooth 90-degree elbow||1 foot, 6 inches|
- The shaft in which the duct is installed shall be constructed and fire-resistant rated as required by the International Building Code.
- Dampers shall be prohibited in the exhaust duct. Penetrations of the shaft and ductwork shall be protected in accordance with Section 607.5.5, Exception 2, of the International Mechanical Code.
- Rigid metal ductwork shall be installed within the shaft to convey the exhaust. The ductwork shall be constructed of sheet steel having a minimum thickness of 0.0187 inch (0.471 mm) (No. 26 gage) and in accordance with SMACNA Duct Construction Standards.
- The ductwork within the shaft shall be designed and installed without offsets.
- The exhaust fan motor design shall be in accordance with Section 503.2 of the International Mechanical Code.
- The exhaust fan motor shall be located outside of the airstream.
- The exhaust fan shall run continuously, and shall be connected to a standby power source.
- The exhaust fan operation shall be monitored in an approved location and shall initiate an audible or visual signal when the fan is not in operation.
- Makeup air shall be provided for the exhaust system.
- A cleanout opening shall be located at the base of the shaft to provide access to the duct to allow for cleaning and inspection. The finished opening shall be not less than 12 inches by 12 inches (305 mm by 305 mm).
- Screens shall not be installed at the termination.
Exception: This section shall not apply to one- and two-family dwellings.
- Closer than 10 feet (3048 mm) from an appliance vent outlet, a vent opening from a plumbing drainage system or the discharge outlet of an exhaust fan, unless the outlet is 3 feet (914 mm) above the outside air inlet.
- Where there is the presence of objectionable odors, fumes or flammable vapors; or where located less than 10 feet (3048 mm)above the surface of any abutting public way or driveway; or where located at grade level by a sidewalk, street, alley or driveway.
- A hazardous or insanitary location or a refrigeration machinery room as defined in the International Mechanical Code.
- A room or space, the volume of which is less than 25 percent of the entire volume served by such system. Where connected by a permanent opening having an area sized in accordance with Section 618.2, adjoining rooms or spaces shall be considered as a single room or space for the purpose of determining the volume of such rooms or spaces.
Exception: The minimum volume requirement shall not apply where the amount of return air taken from a room or space is less than or equal to the amount of supply air delivered to such room or space.
- A room or space containing an appliance where such a room or space serves as the sole source of return air.
Exception: This shall not apply where:
- The appliance is a direct-vent appliance or an appliance not requiring a vent in accordance with Section 501.8.
- The room or space complies with the following requirements:
- The return air shall be taken from a room or space having a volume exceeding 1 cubic foot for each 10 Btu/h (9.6L/W) of combined input rating of all fuel-burning appliances therein.
- The volume of supply air discharged back into the same space shall be approximately equal to the volume of return air taken from the space.
- Return-air inlets shall not be located within 10 feet (3048 mm) of a draft hood in the same room or space or the combustion chamber of any atmospheric burner appliance in the same room or space.
- Rooms or spaces containing solid fuel-burning appliances, provided that return-air inlets are located not less than 10 feet (3048 mm) from the firebox of such appliances.
- A closet, bathroom, toilet room, kitchen, garage, boiler room, furnace room or unconditioned attic.
- Where return air intakes are located not less than 10 feet (3048 mm) from cooking appliances and serve only the kitchen area, taking return air from a kitchen area shall not be prohibited.
- Dedicated forced air systems serving only a garage shall not be prohibited from obtaining return air from the garage.
- A crawl space by means of direct connection to the return side of a forced-air system. Transfer openings in the crawl space enclosure shall not be prohibited.
Floor-mounted-type unit heaters shall be installed with clearances to combustible materials at the back and one side only of not less than 6 inches (152 mm). Where the flue gases are vented horizontally, the 6-inch (152 mm) clearance shall be measured from the draft hood or vent instead of the rear wall of the unit heater. Floor-mounted-type unit heaters shall not be installed on combustible floors unless listed for such installation.
- The underside of the combustible material or metal cabinet above the cooking top is protected with not less than 1/4-inch (6 mm) insulating millboard covered with sheet metal not less than 0.0122 inch (0.3 mm) thick.
- A metal ventilating hood constructed of sheet metal not less than 0.0122 inch (0.3 mm) thick is installed above the cooking top with a clearance of not less than 1/4 inch (6.4 mm) between the hood and the underside of the combustible material or metal cabinet. The hood shall have a width not less than the width of the appliance and shall be centered over the appliance.
- A listed cooking appliance or microwave oven is installed over a listed cooking appliance and in compliance with the terms of the manufacturer's installation instructions for the upper appliance.
Refrigerators shall be provided with adequate clearances for ventilation at the top and back, and shall be installed in accordance with the manufacturer's instructions. If such instructions are not available, at least 2 inches (51 mm) shall be provided between the back of the refrigerator and the wall and at least 12 inches (305 mm) above the top.
Air-conditioning appliances installed in rooms other than alcoves and closets shall be permitted to be installed with reduced clearances to combustible material, provided that the combustible material is protected in accordance with Table 308.2.
Where the air-conditioning appliance is installed within a space separated from the spaces served by the appliance, the air circulated by the appliance shall be conveyed by ducts that are sealed to the casing of the appliance and that separate the circulating air from the combustion and ventilation air.
|CHIMNEY HEIGHT (feet)||MINIMUM PERMANENT FREE OPENING (square inches)a|
|Appliance input rating (Btu per hour)|